Did you know your dog can laugh?

Our current dog does not seem too much like a laugher, but some of our past dogs have. I suspect I would recocognize the sound that researchers say is the equivilent of laughter.

Researchers at the Spokane County Regional Animal Protection Service in Washington state say sometimes a bark is just a bark — but a long, loud panting sound has real meaning.
They say the long, loud pant is the sound of a dog laughing, and it has a direct impact on the behavior of other dogs...When they played the sound of a dog panting over the loudspeaker, the gaggle of dogs at the shelter kept right on barking. But when they played the dog version of laughing, all 15 barking dogs went quiet within about a minute.

Now what would REALLY amaze me would be if they discovered CAT laughter. Or at least discovered it in more than a theoretical sense. Felines seem WAY too serious to me.